An Examination of the Relationships between Eating-Disorder Symptoms, Difficulties with Emotion Regulation, and Mental Health in People with Binge Eating Disorder

Eating disorders, such as binge eating disorder, are commonly associated with difficulties with emotion regulation and mental-health complications. However, the relationship between eating-disorder symptoms, difficulties with emotion regulation, and mental health in people with binge eating disorder is unclear. Thus, we investigated associations between eating-disorder symptoms, difficulties with emotion regulation, and mental health in 119 adults with binge eating disorder. Participants were assessed with the Eating Disorder Examination Questionnaire, Loss of Control over Eating Scale, Difficulties in Emotion Regulation Scale, Depression Anxiety and Stress Scale, and the 12-Item Short Form Survey at the pre-treatment phase of a randomized controlled trial. Structural-equation-modelling path analysis was used to investigate relationships between variables. We found that (1) eating-disorder behaviors had a direct association with depression, anxiety, and stress; (2) depression, psychological stress, difficulties with emotion regulation, and eating-disorder psychopathology had a direct association with mental-health-related quality of life; and (3) eating-disorder psychopathology/behaviors and stress had a direct association with difficulties with emotion regulation. Our findings show that depression, stress, difficulties with emotion regulation, and eating-disorder psychopathology were related in important ways to mental-health complications in people with binge eating disorder.


Introduction
Binge eating disorder (BED) is an eating disorder characterized in the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5) by recurrent binge-eating episodes that have occurred at least once a week for the past three months [1]. Binge-eating episodes are defined as the ingestion of an amount of food that is larger than most people would consume under similar circumstances, accompanied with a sense of loss of control over eating [1]. The DSM-5 criteria for BED also require that people experience at least three of the following five features: (1) eating much more quickly than normal; (2) eating until

Study Design and Participants
We assessed data from pre-treatment measures of participants of a randomized controlled trial that investigated the efficacy of two different online treatment programs for people with BED and comorbid overweight or obesity [15]. Participants' inclusion criteria were (1) age > 18 years; (2) BED, according to the DSM 5 criteria [1]; (3) body mass index (BMI) > 27 and <45 kg/m 2 ; (4) being literate; (5) access to a computer with internet; (6) access to a private room to participate in the online therapy sessions; (7) time available to participate in the whole program; and (8) access to a scale and stadiometer to measure their body weight and height. Exclusion criteria were (1) having bariatric surgery in the previous 24 months; (2) simultaneous participation in another treatment for weight loss or binge eating; (3) clinical conditions that interfere with weight control (e.g., Prader-Willi syndrome, Cushing's syndrome); (4) being pregnant; and (5) severe psychiatric disorder (i.e., schizophrenia, bipolar disorder) or a high suicide risk.
Recruitment of participants from the general community occurred via advertisements on the University of São Paulo's social media from August 2020 to June 2022. The advertisement indicated that the research project offered online group therapy for people with BED and comorbid overweight or obesity, and included a link to a survey that could be completed by people that were interested in participating in the randomized controlled trial. This link led to an online screening survey with questions that assessed the inclusion/exclusion criteria, demographic characteristics, and contact information. Potentially eligible participants were invited for a semi-structured clinical interview via videoconference with a member of the research team. The interviewers assessed whether participants met the DSM-5 criteria for BED described in Table 1. Participants were also required to measure their body weight and height before the interview, and to provide this information to interviewers. Binge-eating episodes were associated with three or more of the following five criteria: 1.
Eating much more rapidly than normal.

3.
Eating large amounts of food when not feeling physically hungry.

4.
Eating alone because of feeling embarrassed by how much one is eating.

5.
Feeling disgusted with oneself, depressed, or very guilty afterward.

Ethics
The study was approved by the Research Ethics Committee of the University of São Paulo's Faculty of Medicine Hospital (CAAE: 19551419.1.0000.0068) in Brazil.

Demographic Characteristics
A self-report questionnaire was used to collect information on age, sex, race, body weight, height, occupation, marital status, and income.

Eating Disorder Examination Questionnaire (EDE-Q)
The EDE-Q is a widely used 28-item self-report questionnaire derived from the "gold standard" interview for the assessments of eating disorders, namely the Eating Disorder Examination [16]. The EDE-Q was used to assess the quantity of objective and subjective binge-eating episodes, as well as the severity of eating-disorder psychopathology in the past 28 days. The EDE-Q generates a global score that is obtained by averaging the subscales (i.e., dietary-restraint, weight-concern, shape-concern, and eating-concern) scores, with higher scores indicating greater eating-disorder psychopathology. We used participants' EDE-Q global scores to assess the severity of eating-disorder psychopathology in our study. Overall, the EDE-Q is a reliable and valid measure of eating-disorders symptoms [17]. We used an unpublished Brazilian-Portuguese version of the EDE-Q that was adapted from the European Portuguese EDE-Q and was previously used in research in Brazil [18,19]. In this study sample, Cronbach's alpha (α) for the item pool of EDE-Q global score was 0.70.

Loss of Control over Eating Scale (LOCES)
The experience of loss of control over eating constitutes a clinically significant feature of eating disorders. However, this feature is assessed only in a dichotomous "yes or no" manner in the EDE-Q, and this may lead to imprecise assessments. Therefore, the LOCES was used in the current study to complement assessments from the EDE-Q. The LOCES is a 24-item self-report scale that is used to assess the severity of a core feature of eating disorders, namely the loss of control over eating [20]. Each item is rated on a 5-point Likert scale that ranges from 1 ("never") to 5 ("always"), which is averaged to generate a total score. Higher score on the LOCES indicate more severe loss of control over eating in the past 28 days. The LOCES shows good internal consistency and test-retest reliability, as well as convergent and discriminant validity [20]. We used a Brazilian-Portuguese version of the LOCES to assess loss of control over eating [21]. Cronbach's alpha for the item pool of LOCES in this study was 0.91.

Difficulties in Emotion Regulation Scale (DERS)
The DERS is a 36-item self-report scale that is widely used to assess clinically relevant difficulties in emotion regulation [8]. The DERS is used to assess the following 6 dimensions of difficulties with emotion regulation: lack of awareness of emotional responses, lack of clarity of emotional responses, non-acceptance of emotional responses, limited access to emotion-regulation strategies perceived as effective, difficulties controlling impulses when experiencing negative emotions, and difficulties engaging in goal-directed behaviors when experiencing negative emotions [8]. Each item is rated on a 5-point Likert scale of 1 ("almost never") to 5 ("almost always"). For this study, we used only the total score of all 36 items, with higher scores indicating increased difficulties with emotion regulation. The DERS shows good construct validity, good internal consistency, and good discriminative ability [22]. The Brazilian-Portuguese version of the DERS was used in our study [23]. In this study sample, Cronbach's alpha (α) for the total item pool of DERS was 0.86.

Depression, Anxiety and Stress Scale (DASS-21)
The DASS-21 is a self-report scale with 21 items that is used to assess the magnitude of symptoms of depression (7 items), anxiety (7 items), and psychological stress (7 items) in both clinical and non-clinical samples [24]. Each item is rated on a 4-point Likert scale from 0 ("did not apply to me at all") to 3 ("applied to me very much or most of the time") assessing the severity of symptoms over the past week. For this study, the subscale scores were used separately with higher scores indicating more severe symptoms of depression, anxiety, or psychological stress. The DASS-21 is a valid measure of dimensions of depression, anxiety, and psychological stress, and shows appropriate construct validity and high reliability [25]. We used the Brazilian-Portuguese-validated version of the DASS-21 in our study [26]. Cronbach's α for our sample was 0.92 for the total DASS-21 item pool, 0.89 for the depression subscale, 0.77 for the anxiety subscale, and 0.81 for the psychological stress subscale.

12-Item Short Form Survey (SF-12)
The SF-12 is a reliable measure used to assess mental and physical HRQoL in different population groups [27]. The SF-12 is also a valid and sensitive measure of impairment in HRQoL in people with eating disorders [28]. The survey scores are categorized into two domains, a physical-composite-scale (PCS) score and a mental-composite-scale (MCS) score, each including six items. In our study we analyzed only mental HRQoL using the MCS score. Elevated scores on the MCS indicate greater mental HRQoL. We used a Brazilian-Portuguese version of the SF-12 to assess participants' mental HRQoL [29]. Cronbach's alpha (α) for the MCS item pool was 0.70.

Statistical Analyses
Firstly, we documented the descriptive data for demographic characteristics (i.e., age, gender, race, occupation, marital status, income) and clinical features (i.e., eating-disorder psychopathology, objective binge-eating episodes, subjective binge-eating episodes, loss of control over eating, difficulties with emotion regulation, depression, anxiety, psychological stress, and mental HRQoL. Continuous variables were presented as means and standard deviation (SD); and categorical variables were presented as percentages. Next, we examined the associations of demographic characteristics with mean scores for all clinical features. We calculated a correlation matrix to explore potential correlations among clinical features. Theoretically relevant indices that showed a significant (p < 0.05) bivariate relationship with any of the clinical features were entered into the path model within a structural-equation-modelling (SEM) framework [30,31]. The SEM was designed to test the following associations: (1) inter-relationships among clinical features; (2) paths leading from objective or subjective binge-eating episodes, eating-disorder psychopathology, loss of control over eating, psychological stress, and anxiety, to difficulties with emotion dysregulation, depression, and mental HRQoL; (3) direct and indirect paths leading from binge eating, eating-disorder psychopathology, loss of control over eating, psychological stress, difficulties with emotion regulation, and depression, to mental HRQoL. Model fitness was assessed according to conventional criteria, including a non-significant chi-square test; comparative fit index (CFI) > 0.90; the Tucker-Lewis Index (TLI) > 0.90; the root-mean-square error of approximation (RMSEA) < 0.08; and the standardized root-mean-square residual (SRMR) < 0.08 [32][33][34]. The analyses were performed in SPSS v. 27 [35] and Mplus 7.1. [33].

Participants' Demographic Characteristics
One hundred and nineteen participants were included in our study (see Appendix A). The demographic characteristics of all 119 participants are shown in Table 2. The participants' mean age was 36 years (SD, 8.8); 21.8% (n = 26) were 18 to 29 years of age, 45.4% (n = 54) were 30-39 years of age, and 32.8% (n = 39) were 40-59 years of age. Most participants were female (n = 108, 90.8%). Three quarters of the participants were from a white ethnicity group and the remainder (25%) consisted of black or other ethnic backgrounds. Almost two-thirds (66%) of the participants were full-time or part-time employed, and a similar proportion (65%) reported to be either married or living with a partner (see Table 2).

Bivariate Analyses
Association of participant's demographic characteristics and mean scores for all clinical features are shown in Table 1. There were no significant differences observed for any of the clinical features by participants' demographic characteristics. Table 3 shows the correlation matrix of all clinical features.

Correlates of Loss of Control over Eating
Objective binge-eating episodes (β = 0.20, p < 0.05) and eating-disorder psychopathology (β = 0.44, p < 0.01) showed significant direct associations with loss of control over eating.

Discussion
Our study investigated relationships between eating-disorder symptoms, difficulties with emotion regulation, general mental health, and mental HRQoL in adults with BED. Overall, we found that eating-disorder behaviors and psychopathology were associated with poorer mental health in participants included in our study. For instance, we found that: (1) objective binge eating had a direct association with anxiety; (2) subjective binge eating had a direct association with psychological stress; (3) loss of control over eating had a direct association with anxiety and depression; and (4) eating-disorder psychopathology had a direct association with mental HRQoL. Moreover, we found that eating-disorder psychopathology and loss of control over eating had a direct association with less effective emotion regulation. Lastly, we found that depression and psychological stress had a direct association with mental HRQoL, and psychological stress had a direct association with less effective emotion regulation.
Our study showed that several factors can be associated with poor mental HRQoL in people with BED. Our findings suggest that it is important to address a range of mentalhealth problems, i.e., depression, psychological stress, difficulties with emotion regulation, and eating-disorder psychopathology, to enhance mental HRQoL in this population. Thus, people with BED may require comprehensive assessment and treatment approachesrather than treatments focused only on the cessation of binge-eating episodes-to improve their mental health. For instance, it is important that clinicians working with clients with BED assess their clients' levels of depression, psychological stress, and difficulties with emotion regulation, and provide the required specialized therapies to address these complications when necessary. Clinicians can ask their clients with BED to complete self-report scales such as the DASS-21 and DERS to assess their mental-health status and difficulties with emotion regulation [8,24]. It may also be useful to comprehensively assess eating-disorder psychopathology in clients with BED, using measures such as the semistructured interview for the investigation of eating-disorder symptoms, the Eating Disorder Examination [16]. This assessment can enable the identification of specific characteristics of the eating-disorder psychopathology that are prominent in each client, so that clinicians can address them and potentially prevent the deterioration of mental HRQoL. Moreover, it is noteworthy that some treatments for eating disorders can also induce improvements in general mental health. For instance, cognitive behavior therapy (CBT) for eating disorders can reduce depression, anxiety, mood intolerance, low self-esteem, clinical perfectionism, and interpersonal difficulties in people with BED [16,36,37].
Our findings also enable a better understanding of the occurrence of difficulties with emotion regulation in people with BED. We found that eating-disorder psychopathology, loss of control over eating, and psychological stress had a direct association with less effective emotion regulation in our sample of adults with BED. This finding suggests that a reduction in eating-disorder symptoms through CBT [38], and reduction in psychological stress via access to specialized treatments (e.g., mindfulness-based stress reduction) [39] may facilitate effective emotion regulation in people with BED. The attenuation of difficulties with emotion regulation is particularly important, as we found that such difficulties have a direct effect on depression and poor mental HRQoL in this population. Taking this into consideration, psychological therapies that focus on training in emotion-regulation skills (e.g., dialectical behavior therapy) are known to be useful to address mental-health complications and eating-disorder symptoms in people with BED and comorbid difficulties with emotion regulation [40], but are under researched [41,42]. Overall, it may be beneficial that clinicians working with treatment models that focus mostly on the reduction of eating-disorder symptoms consider adding skills training on emotion-regulation and stress-management interventions to their treatment plans for clients with BED.
In addition to direct relationships between eating-disorder symptoms, difficulties with emotion regulation, and mental health in people with BED, we also found significant indirect relationships. These indirect relationships were described in detail in the Results section; nonetheless, here we provide a summary: (1) objective and subjective binge eating, loss of control over eating, and anxiety showed an indirect association with mentalhealth-related quality of life; (2) eating-disorder psychopathology showed an indirect association with depression; and (3) anxiety showed an indirect association with difficulties with emotion regulation. We found multiple direct and indirect relationships between eating-disorder symptoms, difficulties with emotion regulation, and poor mental health in people with BED. Overall, the relationships that were found in our study provide a better understanding of the complexity of psychopathology associated with BED. However, our findings do not substitute individualized clinical assessments of symptoms of BED and associated mental-health complications. Clinicians working with clients with BED will need to conduct individual assessments of eating-disorder symptoms, difficulties with emotion regulation, and mental-health status, to understand how these factors influence each other in order to plan individualized treatments.
Our findings also have implications for research on treatment outcomes for people with BED. A significant number of treatment trials for BED focus on the reduction or abstinence of binge eating as an outcome, and neglect broader aspects of mental health and mental HRQoL [43]. This limits the understanding of the efficacy and effectiveness of treatments for BED. Thus, the inclusion of general measures of mental-health status (e.g., DASS-21 [24]) in treatment trials for people with BED is necessary to investigate potential effects of these treatments on overall mental health. Moreover, future research-including longitudinal studies-is necessary to elucidate causality, mediation, and bidirectional analyses between eating-disorder symptoms, difficulties with emotion regulation, and mental health in people with BED.
This study has several strengths and limitations. Notable strengths include the use of an advanced statistical analytical approach (i.e., the structural-equation-modelling technique)-to examine complex causal models. Additionally, we included several measures of eating-disorder symptoms (i.e., EDE-Q, LOCES) and aspects of mental health (i.e., DASS-21, DERS, SF-12 MCS score) in a sample of adults with BED. The combined use of these different statistical analyses and measures allowed us to examine relationships between eating-disorder symptoms, difficulties with emotion regulation, and mental health, in a comprehensive and reliable manner. The main limitation of our study is that we used a cross-sectional design, and causal inferences cannot be made. Another potential limitation is that 90.8% of the study sample was female. There were no significant differences between males and females in difficulties-with-emotion-regulation scores in our sample; however, our findings may not be generalizable to males with BED or people with BED in regions with significant cultural differences. Additionally, a potential limitation is that all data used for statistical analyses in this study were obtained via self-report measures. It is possible that we could have obtained more accurate clinical data if instead of self-report measures we used semi-structured interviews, such as the Eating Disorder Examination [16]. A final limitation of our study is that while we thoroughly examined effects of eating-disorder symptoms on mental-health status, we did not examine relationships in the opposite direction (i.e., potential effects of mental-health status on eating-disorder symptoms).
In summary, our study found multiple direct and indirect relationships between eating-disorder symptoms, difficulties with emotion regulation, and mental-health status in adults with BED. We found that depression, psychological stress, difficulties with emotion regulation, and eating-disorder psychopathology had a direct association with mental HRQoL. Additionally, eating-disorder psychopathology, loss of control over eating, and psychological stress had a direct association with difficulties with emotion regulation. Thus, research involving the evaluation of clinical-trial outcomes as well as real-world treatment plans for people with BED should address comprehensively the symptoms of depression, psychological stress, difficulties with emotion regulation, eating-disorder psychopathology (i.e., dietary restraint, excessive concerns about body shape, weight, and eating) and loss of control over eating.  Data Availability Statement: Data available on request, due to restrictions. The data presented in this study are available on request from the corresponding author. The data are not publicly available, due to privacy reasons. All responses to recruitment (completed an online selfreport screening questionnaire) n=3181

Conflicts of Interest
Not contacted by the research team n=2933 Research team attempted to invite for an interview n=248 Contactable n=195 Not contactable n=53 Excluded from the study: Did no meet criteria for BED n=38 BMI incompatible with inclusion criteria n=6 Other treatment for binge eating or weight loss n=16 Pregnancy n=2 Work at the time of treatment sessions n=11 No private place to participate in online sessions n=1 Suicidal ideation n=4 Declined offer of enrolment n=2 Completed the pre-treatment assessments and were included in the study n=119 Figure A1. Participant flow.